Synthesis, photocrosslinking characteristics, and biocompatibility evaluation of N-vinyl pyrrolidone/polycaprolactone fumarate biomaterials using a new proton scavenger

Photocrosslinkable and biodegradable polymeric networks were formulated based on N-vinyl pyrrolidone-poly(epsilon-caprolactone fumarate) (NVP/PCLF) compositions for hard tissue engineering applications using a new proton scavenger, propylene oxide (PO). The synthesized macromers; were obtained as a white clear paste with no colorization. The obtained macromers were thoroughly characterized using spectroscopic (NMR and FT-IR) and chromatographic (gel permeation chromatography (GPC)) techniques. Photocrosslinking of the PCLF/NVP compositions was achieved using camphorquinone and dimethyl toluidine (DMT) as a photoinitiator system. The cytocompatibility of the macromers and their corresponding networks were evaluated via MTT assay. Characterization of the networks indicated the importance of NVP content on the network properties. Sol fraction studies indicated that more than 90% of the PCLFs were crosslinked over the studied range of PCLF/NVP compositions; however most of the NVP above a stoichiometric ratio of one NVP to fumerate unit remained unreacted. It was also found that in the concentrations more than 10% NVP, the unreacted NVP monomer neither participated in the crosslinking reaction nor homopolymerized to poly(vinyl pyrrolidone) (PVP). The elastic modulus (G') and estimated molecular weight between crosslinks also confirmed that at the higher NVP content the PCLF photocrosslinking was hindered. Copyright (C) 2008 John Wiley & Sons, Ltd.